1. Field of the Invention
This invention relates generally to an improved toggle bolt fastener for hanging or through bolt mount of heavy objects on a hollow wall, and more particularly, to a toggle bolt wherein the stabilizer provides a snug fit between the toggle bolt exterior and the wall aperture perimeter thereby increasing the available shearout area to reduce wall distortion or damage. A bolt head spacer may be utilized with the sleeve to act as a seat for certain hanging objects.
2. Description of the Prior Art
Blind anchors and fasteners for attaching heavy objects to hollow walls are well known in the art. Typically, a toggle bolt fastener is employed comprising a threshold elongated bolt connectible to a toggle having one or more collapsible normally open toggle wings, threadably engaged on one side, which are inserted longitudinally through a hole in a wall of sufficient diameter to permit the transit of the toggle through the wall whereupon the toggle opens or moves perpendicular to the bolt shaft preventing its movement back through the wall hole. Such a toggle bolt is disclosed in U.S. Pat. No. 4,732,520 issued to Giannuzi. When the toggle is fully inserted through the wall thickness, the toggle wings move perpendicular to the bolt axis to provide a bearing surface against the wall interior surface to react loads imposed on the bolt from supporting heavy objects. A prime disadvantage of a toggle bolt is that the wall hole diameter must be large enough to accept the toggle diameter which exceeds greatly the bolt diameter leaving a circumferential space that results in sloppy fit between the bolt shaft and the wall hole after the assembly is installed. Accordingly, the bolt shaft may be shifted by the load away from a horizontal position with the bolt head low and the toggle bolt high resulting in possible wall damage and weakened support. Another disadvantage is that the bolt may slip during installation or mounting of an object through the enlarged hole and into the hollow wall space.
Other types of prior art hollow wall fasteners are of the type disclosed in U.S. Pat. No. 4,043,245 issued to Kaplan. The Kaplan patent overcomes the problems inherent in standard toggle bolt arrangements as described above through the use of a custom fit washer and wall anchor plate. Likewise, U.S. Pat. No. 4,075,924 issued to McSherry, et al. discloses a hollow wall anchor comprising a custom built retaining washer and elongated flexible leg members for insertion through a hole in the wall. Such complex hollow wall fasteners differ greatly from the conventional expandable wing toggle in complexity of installation and operation, without enhancing results.
Still other types of prior art in this area disclose "lug anchors" wherein an expandable insert is utilized to react applied load solely through the friction created between the insert's outer surface and the materials within which it is mounted. These suffer from reduced effectiveness caused by material thermal expansion and contraction, and vibration induced material deterioration.
Accordingly, there exists a need for a toggle bolt type of hollow wall blind fastener wherein a toggle bolt shaft can fit firmly in the wall aperture to ensure a stable wall mount for hanging objects on a wall.